<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>15.includes方法原理实现</title>
</head>
<body>
  <script>
    let arr = [1,2,3,4,5];
    function includes(array,find){
      for(const value of array){
          if(value === find) return true;
      }
      return false;
    }
    console.log(includes(arr,5));
  </script>
</body>
</html>